Explosive



Patented June 28, 1932 UNITED STATES PHOKION PATENT OFFICE NAOUM, OF COLOGNE, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

E. I. DU FONT DE NEMOURS'& CO., 01 WILMINGTON, DELAWARE EXPLOSIVE No Drawing. Application filed January 3, 1931, Serial No. 506,504, and in Germany .Tune 4, 1930.

This invention relates to the process of producing an explosive utilizing calcium nitrate.

Powder and explosives 5 .from the various types of salt petre or the nitrates of alkalies and earth alkalies and also calcium nitrate, which serve as oxygen carriers. Potassium nitrate, sodium nitrate and also barium nitrate have been in use for a long time, and the firstnitrate mentioned has been used on a very large scale not only in the manufacture of black powder and salt petre blasting powder, but also for shattering explosives, for example dynamite. In pyrotechnics, strontium nitrate has also been used. However, calcium nitrate has not been employed to any extent in the powder and explosive industry.

The reason for the non-use of calcium nitrate 1n the explosive industry is due undoubtedly to the strong hygroscopicity of calcium nitrate and its substantially high water of crystallization content which renders it substantially inert as an explosive ingredient.

The water of crystallization content must also be gasified during the explosion and this is attained with difficulty, Therefore, notwithstanding the better action which cal 80 cium nitrate will exert as explosive constituent by reason of the lower disassociation temperature of the calcium carbonate formed in the explosive conversion of the total explosive, as compared to that of the alkali carbonate, calcium nitrate has not been used for the production of high explosives or mixtures resembling black powder to any extent.

In patent literature probably theonly exceptions which show the use of calcium nitrate in shattering explosives is found in United States Patents 'Nos. 1,671,792 and 1,671,793, granted to Buren I. Stoops upon May 29th, 1928. According to these patents the calcium nitrate is melted in its water of crystallization and is then admixed with voluminous carbon carriers and is then left again to-harden. This method produces ex+ plosives of low density, shattering'force and.

power and are useful only as so-called wet terdynamite and these explosivesonly concan be produced tain the calcium nitrate in its water of crystallization state. During the explosion of course, this water of crystallization must be given up and gasified and this reduces the efliciency of the explosive.

Efforts have also recently been made to make use of calcium nitrate for the production of blasting powder mixtures by dissolving the calcium. nitrate in Water and then using the solution to impregnate the suitable voluminous carbon carriers. The mixture is then dried at high temperatures, over 100 C. in order to remove the water and the water of crystallization." The removal of the water of crystallization according to this process is never entirely complete and the process is also dangerous since the finished explosive. must be heated to a relatively high temperature which will cause ignition of the explosive in many instances. This method produces relatively light low power explosives which are extraordinarily hygroscopic and which will lose very easily their explosive power by taking up even a small quantity of water.

All of the above mentioned defects which have been an obstacle to the use of calcium nitrate as an explosive constituent are eliminated by the hereinafter described process according to which the calcium nitrate is completely dehydrated before being mixed with the other constituents of the explosive.

By this process dangerous heating of the finished explosive mixture is avoided.

It has beenfound that commercial calcium nitrate can be completely dehydrated at a suitable high temperature over 100 C. and the calcium nitrate will disintegrate into an extremely fine powder which after suitable cooling, is eminently suitable /for the production of a homogeneous explosive mixture. The danger of taking up water in the dehydrated productmay be completely overcome by maintaining suitable manufacturing precautions and measures.

A remarkable attribute of the calcium nitrate when prepared in this way is the excellent absorptive capacity of the pnlverulent dehydrated calcium nitrate for nitro-glycerinc and similar explosive oils. A special ading special binders or absorbents.

vantage has also been observed in the possibility of adding large quantities of nitroglycerine, etc. to mixtures having a basis of calcium nitrate without the necessity of add- In fact, the mixtures produced by this process are so sensitive to detonation and have such power and efiiciency of explosion so as to guarantee the efficiency of the product even if after a lapse of time the explosive should again take up some water of crystallization.

Explosives are produced according to the present process in the following manner.

Commercial calcium nitrate containing about 15% water of crystallization is melted by means of high pressure steam in its water of crystallization and then dehydrated at a temperature exceeding 100 (1'. whereby the calcium nitrate will fall in a powder which is as fine as flour. This powder is then cooled and then admixed for example, by means of mixing cylinders or drums, with the other constituents of the explosive and then the desired quantity of nitro-glycerine or other explosive oils are added to the mixture in a kneading or similar machine. After the explosive mass has been put up in cartridges, the latter are immersed in paraifine or the explosive is wrapped in paraiiined paper. The following, are. examples of compositions of various mixtures made according to the present process.

Lead block bulge test Per cent 1. Calcium nitrate, dehydrated 7 Wood charcoal %g}260 com:

Nitroglycerine 2. Calcium nitrate, dehydrated 66 Woodcharcoal 14 280 ccm. Nitroglyceriue 20 3. Calcium nitrate, dehydrated 62 Trinitrotoluol 18 Sawdust 6 285 ccm. Wood charcoal 4 Nitroglycorino 10 A comparison of the above mixtures in regard to their force, eiiiciency and shattering power over those having a sodium nitrate.

base is shown by the fact that an explosive manufactured according to formula 2 above, which instead of calcium nitrate contained the same quantity of sodium nitrate resulted in only 190 com., and one manufactured of sodium nitrate according to formula 3 resulted in onlyf220 ccm. in-lead block bulge tests. The superiority of the mixtures manufactured according to this process is thereby conclusively proved.

It is'to be understood that various changes and modifications may be made in the above process, but all such changes and modifications areclaimed, as come within the spirit and scope of the following claims.

I claim:

1. A process for the production of shattering explosives comprising dehydrating calcium nitrate at an elevated temperature, then cooling said nitrate and then mixing said nitrate while in pulverulent form with a. sensitizer.

2. A process for the production of shattering explosives comprising dehydrating calcium nitrate at an elevated temperature, then cooling said nitrate and then mixing said nitrate while in pulverulent form with a sensitizer and carbon.

3. The method of producing an explosive whichcomprises dehydrating calcium nitrate and then mixing said dehydrated calcium nitrate with a sensitizer.

4. The method of producing an explosive which comprises dehydrating calcium nitrate and then mixing said dehydrated calcium nitrate with a sensitizer and carbon.

5. The method of producing an explosive which comprises dehydrating calcium nitrate and then mixing said dehydrated calcium nitrate with a sensitizer and charcoal. 6. The method of producing an explosive which comprises dehydrating calcium nitrate and then mixing said dehydrated calcium nitrate with nitro-glycerine.

7. The method of producing an explosive which comprises dehydrating calcium nicharcoal and nitro-glycerine.

12. An explosive comprising about 70% dehydrated calcium nitrate, about 15% wood charcoal, and about 15% nitro-glycerine.

13. An explosive comprising about 62% dehydrated calcium nitrate, about 18% trinitrotoluol, about 6% sawdust, about 4% wood charcoaland about 10% nitro-glycerine.

In testimony whereof I have signed my name to this specification.

PHOKION NAOUM. 

